Base de dados : MEDLINE
Pesquisa : D05.500.049 [Categoria DeCS]
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[PMID]:29429161
[Au] Autor:Li L; Duan XJ; Sun Y; Lu Y; Xu HY; Wang QZ; Wang HY
[Ad] Endereço:Department of Pathology, Fuwai Hospital, Chinese Academy of Medical Sciences, Beijing 100037, China.
[Ti] Título:[Classification of cardiac amyloidosis: an immunohistochemical analysis].
[So] Source:Zhonghua Bing Li Xue Za Zhi;47(2):105-109, 2018 Feb 08.
[Is] ISSN:0529-5807
[Cp] País de publicação:China
[La] Idioma:chi
[Ab] Resumo:To evaluate the sensitivity and specificity of immunohistochemistry (IHC) in the classification of cardiac amyloidosis on endomyocardial biopsy (EMB) and heart allograft. Twenty cardiac tissues from 19 patients at Fuwai Hospital from January, 1990 to April, 2017 with histopathologic features of amyloidosis and Congo red staining positivity were included. IHC was performed with monoclonal antibodies against AA amyloid and polyclonal antibodies against transthyretin (ATTR), λ-light chain (AL-λ), κ-light chain (AL-κ), ApoAâ… , ApoAâ…¡, ApoA â…£ and ß(2)-microglobin. The extent of interstitial staining was evaluated by light microscopy, and three patterns were recognized; these included diffuse pericellular pattern, discrete pericellular pattern, and nodular pattern. Two patterns of vascular deposition were also noted, including arterial pattern and venous pattern. Endocardial involvement was also assessed and recorded. Nineteen cases were divided into three groups according to the pattern of proteins expression in specimens. The first group (5 cases) only showed single protein expression on EMB. The second group (6 cases) showed more than one protein expression, but one of them was intensely stained or any staining of any protein together with ApoA â…£ co-staining. The third group (8 cases) also showed more than one protein expression and all of them had intense staining. Amyloid deposits were successfully subtyped as AL-λ, ATTR, AL-κ and ApoAâ… by IHC in the former two groups with the sensitivity of 11/19. In the third group, amyloid deposits could not be subtyped by immunohistochemistry due to their poor specificity. The pericellular pattern tended to favor AL over ATTR amyloidosis and vascular deposition tended to favor ATTR. Amyloid deposits can be reliably subtyped in diagnostic cardiac specimens using IHC. The co-deposition of chaperon proteins, the distribution of amyloid proteins and clinical features are also auxiliary to subtype cardiac amyloidosis.
[Mh] Termos MeSH primário: Amiloidose/patologia
Cardiomiopatias/patologia
[Mh] Termos MeSH secundário: Amiloide/análise
Neuropatias Amiloides Familiares/patologia
Anticorpos Monoclonais/análise
Apolipoproteína A-I/análise
Apolipoproteínas A/análise
Biópsia
Seres Humanos
Cadeias kappa de Imunoglobulina/análise
Cadeias lambda de Imunoglobulina/análise
Imuno-Histoquímica
Placa Amiloide/patologia
Sensibilidade e Especificidade
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (APOA1 protein, human); 0 (Amyloid); 0 (Antibodies, Monoclonal); 0 (Apolipoprotein A-I); 0 (Apolipoproteins A); 0 (Immunoglobulin kappa-Chains); 0 (Immunoglobulin lambda-Chains); 0 (apolipoprotein A-IV)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180306
[Lr] Data última revisão:
180306
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180213
[St] Status:MEDLINE
[do] DOI:10.3760/cma.j.issn.0529-5807.2018.02.005


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[PMID]:29339755
[Au] Autor:Rout SK; Friedmann MP; Riek R; Greenwald J
[Ad] Endereço:Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland.
[Ti] Título:A prebiotic template-directed peptide synthesis based on amyloids.
[So] Source:Nat Commun;9(1):234, 2018 01 16.
[Is] ISSN:2041-1723
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The prebiotic replication of information-coding molecules is a central problem concerning life's origins. Here, we report that amyloids composed of short peptides can direct the sequence-selective, regioselective and stereoselective condensation of amino acids. The addition of activated DL-arginine and DL-phenylalanine to the peptide RFRFR-NH in the presence of the complementary template peptide Ac-FEFEFEFE-NH yields the isotactic product FRFRFRFR-NH , 1 of 64 possible triple addition products, under conditions in which the absence of template yields only single and double additions of mixed stereochemistry. The templating mechanism appears to be general in that a different amyloid formed by (Orn)V(Orn)V(Orn)V(Orn)V-NH and Ac-VDVDVDVDV-NH is regioselective and stereoselective for N-terminal, L-amino-acid addition while the ornithine-valine peptide alone yields predominantly sidechain condensation products with little stereoselectivity. Furthermore, the templating reaction is stable over a wide range of pH (5.6-8.6), salt concentration (0-4 M NaCl), and temperature (25-90 °C), making the amyloid an attractive model for a prebiotic peptide replicating system.
[Mh] Termos MeSH primário: Aminoácidos/química
Amiloide/química
Técnicas de Química Sintética/métodos
Peptídeos/química
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Aminoácidos/genética
Aminoácidos/metabolismo
Amiloide/metabolismo
Amiloide/ultraestrutura
Arginina/química
Arginina/genética
Arginina/metabolismo
Concentração de Íons de Hidrogênio
Microscopia Eletrônica
Origem da Vida
Biossíntese Peptídica/genética
Peptídeos/genética
Peptídeos/metabolismo
Fenilalanina/química
Fenilalanina/genética
Fenilalanina/metabolismo
Cloreto de Sódio/química
Estereoisomerismo
Temperatura Ambiente
Moldes Genéticos
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Amino Acids); 0 (Amyloid); 0 (Peptides); 451W47IQ8X (Sodium Chloride); 47E5O17Y3R (Phenylalanine); 94ZLA3W45F (Arginine)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180305
[Lr] Data última revisão:
180305
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180118
[St] Status:MEDLINE
[do] DOI:10.1038/s41467-017-02742-3


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[PMID]:29381728
[Au] Autor:Belousov MV; Bondarev SA; Kosolapova AO; Antonets KS; Sulatskaya AI; Sulatsky MI; Zhouravleva GA; Kuznetsova IM; Turoverov KK; Nizhnikov AA
[Ad] Endereço:Department of Genetics and Biotechnology, St. Petersburg State University, Universitetskaya nab., St. Petersburg, Russian Federation.
[Ti] Título:M60-like metalloprotease domain of the Escherichia coli YghJ protein forms amyloid fibrils.
[So] Source:PLoS One;13(1):e0191317, 2018.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Amyloids are protein fibrils with a characteristic spatial structure. Amyloids were long perceived as the pathogens involved in a set of lethal diseases in humans and animals. In recent decades, it has become clear that amyloids represent a quaternary protein structure that is not only pathological but also functionally important and is widely used by different organisms, ranging from archaea to animals, to implement diverse biological functions. The greatest biological variety of amyloids is found in prokaryotes, where they control the formation of biofilms and cell wall sheaths, facilitate the overcoming of surface tension, and regulate the metabolism of toxins. Several amyloid proteins were identified in the important model, biotechnological and pathogenic bacterium Escherichia coli. In previous studies, using a method for the proteomic screening and identification of amyloids, we identified 61 potentially amyloidogenic proteins in the proteome of E. coli. Among these proteins, YghJ was the most enriched with bioinformatically predicted amyloidogenic regions. YghJ is a lipoprotein with a zinc metalloprotease M60-like domain that is involved in mucin degradation in the intestine as well as in proinflammatory responses. In this study, we analyzed the amyloid properties of the YghJ M60-like domain and demonstrated that it forms amyloid-like fibrils in vitro and in vivo.
[Mh] Termos MeSH primário: Amiloide/química
Proteínas de Escherichia coli/química
Metaloproteases/química
Multimerização Proteica
[Mh] Termos MeSH secundário: Domínios Proteicos
Estrutura Secundária de Proteína
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Amyloid); 0 (Escherichia coli Proteins); EC 3.4.- (Metalloproteases); EC 3.4.- (YghJ protein, E coli)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180226
[Lr] Data última revisão:
180226
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180131
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0191317


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[PMID]:29372919
[Au] Autor:Karaballi RA; Merchant S; Power SR; Brosseau CL
[Ad] Endereço:Department of Chemistry, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada. christa.brosseau@smu.ca.
[Ti] Título:Electrochemical surface-enhanced Raman spectroscopy (EC-SERS) study of the interaction between protein aggregates and biomimetic membranes.
[So] Source:Phys Chem Chem Phys;20(6):4513-4526, 2018 Feb 07.
[Is] ISSN:1463-9084
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Human diseases characterized by the uncontrolled deposition of insoluble extracellular protein aggregates are collectively referred to as amyloidoses. Such diseases include Alzheimer's, Parkinson's, Huntington's, and prion disease. In Alzheimer's disease, it is believed that amyloid-ß proteins may be responsible for pore and defect formation within cellular membranes, leading to a breakdown of cellular homeostasis causing eventual neuronal death. This theory is referred to as the amyloid pore hypothesis of Alzheimer's disease. In this work, the interaction between a model amyloid-forming protein (insulin) and a biomimetic membrane was studied at the molecular level. Protein at different stages of aggregation was allowed to interact with a biomimetic membrane formed on a nanostructured substrate using Langmuir-Blodgett/Langmuir-Schaefer deposition. Electrochemical surface-enhanced Raman spectroscopy (EC-SERS) was used to monitor the molecular level changes occurring as a result of this interaction. Based on the results it was observed that oligomers and protofibrils caused the most significant membrane deterioration whilst native protein appeared to play a protective role. To the best of our knowledge, this work represents the first EC-SERS investigation of protein aggregate-biomembrane interactions, and highlights the usefulness of this tool for studying complex biomolecular interactions.
[Mh] Termos MeSH primário: Amiloide/química
Biomimética
Insulina/química
Bicamadas Lipídicas/química
Agregados Proteicos
[Mh] Termos MeSH secundário: Amiloide/metabolismo
Técnicas Eletroquímicas
Eletrodos
Seres Humanos
Insulina/metabolismo
Bicamadas Lipídicas/metabolismo
Nanopartículas Metálicas/química
Microscopia Eletrônica de Varredura
Microscopia Eletrônica de Transmissão
Nefelometria e Turbidimetria
Prata/química
Análise Espectral Raman
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Amyloid); 0 (Insulin); 0 (Lipid Bilayers); 0 (Protein Aggregates); 3M4G523W1G (Silver)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180226
[Lr] Data última revisão:
180226
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180127
[St] Status:MEDLINE
[do] DOI:10.1039/c7cp06838g


  5 / 13131 MEDLINE  
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[PMID]:29372732
[Au] Autor:Xu L; Bhattacharya S; Thompson D
[Ad] Endereço:Department of Physics, Bernal Institute, University of Limerick, V94 T9PX, Ireland. Damien.thompson@ul.ie.
[Ti] Título:The fold preference and thermodynamic stability of α-synuclein fibrils is encoded in the non-amyloid-ß component region.
[So] Source:Phys Chem Chem Phys;20(6):4502-4512, 2018 Feb 07.
[Is] ISSN:1463-9084
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The heterogeneity of the synucleinopathies, neurological disorders that include Parkinson's disease (PD), indicates that toxicity, seeding/cross-seeding ability, and propagation of α-synuclein (αS) assemblies depend on their distinct structural characteristics or "strain". To examine the molecular signature that encodes the aggregation seed, conformational preference, and thermodynamic stability of full-length αS fibrils, we performed molecular dynamics simulations on two non-amyloid-ß component (NAC) fibril structures, containing residues 61-95 of two distinct αS fibrils. We identified several discrete hot spots in the recognized hydrophobic core of NAC (residues 68-82) that could initiate the early assembly of αS. We show that NAC fibrils inherit the preferred fold of their parent αS fibril, but could switch conformational preference in two fibril mutants K80Q and E83Q under different solution conditions. Similar to αS fibrils, NAC fibrils are also sensitive to temperature and salt concentration. The favorable solvation free energy of NAC fibrils at low temperature (280 K) suggests a propensity for cold-denaturation. Our results indicate that the strain-dependent synucleinopathies may be partially imprinted in the fold-dependent thermodynamic properties of NAC fibrils, providing structural insights into the emerging development of anti-PD treatments that target the NAC region of αS.
[Mh] Termos MeSH primário: Simulação de Dinâmica Molecular
alfa-Sinucleína/química
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Amiloide/química
Seres Humanos
Mutagênese Sítio-Dirigida
Doença de Parkinson/metabolismo
Doença de Parkinson/patologia
Estabilidade Proteica
Estrutura Secundária de Proteína
Termodinâmica
alfa-Sinucleína/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Amyloid); 0 (alpha-Synuclein)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180226
[Lr] Data última revisão:
180226
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180127
[St] Status:MEDLINE
[do] DOI:10.1039/c7cp08321a


  6 / 13131 MEDLINE  
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[PMID]:29357364
[Au] Autor:Seraj Z; Seyedarabi A; Saboury AA; Habibi-Rezaei M; Ahmadian S; Ghasemi A
[Ad] Endereço:Department of Biochemistry, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
[Ti] Título:Unraveling the novel effects of aroma from small molecules in preventing hen egg white lysozyme amyloid fibril formation.
[So] Source:PLoS One;13(1):e0189754, 2018.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:This study investigated for the first time the molecular effectiveness of 'aroma' from three small molecules including a phenol (phenyl ethyl alcohol; PEA) and an aldehyde (cinnamaldehyde; Cin) both containing an aromatic ring, and a diamine (N,N,N,N'- Tetramethylethylenediamine; TEMED) at two different amounts (small; S and large; L) in preventing hen egg white lysozyme (HEWL) amyloid fibril formation using Thioflavin T and Nile red fluorescence assays, circular dichroism spectroscopy, SDS-polyacrylamide gel electrophoresis, atomic force microscopy, dynamic light scattering and HEWL activity test. Interestingly, the results revealed that (1) the aroma of PEA, identified as an active constituent of Rosa damascena, prevented fibril formation since PEA-L was able to trap the oligomeric form of HEWL in contrast to PEA-S where protofibrils but not mature fibrils were formed; (2) Cin, previously shown to prevent fibril formation in the liquid form, was also shown to do so in the aroma form by producing protofibrils and not mature fibrils in both Cin- L and Cin-S aroma forms and (3) the aroma of TEMED-L was able to retain HEWL's native structure completely and prevented both aggregation and fibril formation, while TEMED-S prevented HEWL fibril formation and instead directed the pathway towards amorphous aggregate formation. Furthermore, the ability to trap oligomeric species (by PEA-L aroma) is of great importance for further research as it provides routes for preventing the formation of toxic oligomeric intermediates along the fibrillation pathway. Last but not least, the novelty of this in vitro study on the effect of aroma at the molecular level with a unique experimental set-up using HEWL as a model protein in assessing amyloid fibril formation paves the way for more and detailed studies on the importance of aroma producing molecules and their effects.
[Mh] Termos MeSH primário: Amiloide/metabolismo
Clara de Ovo
Muramidase/metabolismo
Odorantes
[Mh] Termos MeSH secundário: Animais
Galinhas
Dicroísmo Circular
Eletroforese em Gel de Poliacrilamida
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Amyloid); EC 3.2.1.17 (Muramidase)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180215
[Lr] Data última revisão:
180215
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180123
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0189754


  7 / 13131 MEDLINE  
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[PMID]:28467905
[Au] Autor:Ramdzan YM; Trubetskov MM; Ormsby AR; Newcombe EA; Sui X; Tobin MJ; Bongiovanni MN; Gras SL; Dewson G; Miller JML; Finkbeiner S; Moily NS; Niclis J; Parish CL; Purcell AW; Baker MJ; Wilce JA; Waris S; Stojanovski D; Böcking T; Ang CS; Ascher DB; Reid GE; Hatters DM
[Ad] Endereço:Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia.
[Ti] Título:Huntingtin Inclusions Trigger Cellular Quiescence, Deactivate Apoptosis, and Lead to Delayed Necrosis.
[So] Source:Cell Rep;19(5):919-927, 2017 May 02.
[Is] ISSN:2211-1247
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Competing models exist in the literature for the relationship between mutant Huntingtin exon 1 (Httex1) inclusion formation and toxicity. In one, inclusions are adaptive by sequestering the proteotoxicity of soluble Httex1. In the other, inclusions compromise cellular activity as a result of proteome co-aggregation. Using a biosensor of Httex1 conformation in mammalian cell models, we discovered a mechanism that reconciles these competing models. Newly formed inclusions were composed of disordered Httex1 and ribonucleoproteins. As inclusions matured, Httex1 reconfigured into amyloid, and other glutamine-rich and prion domain-containing proteins were recruited. Soluble Httex1 caused a hyperpolarized mitochondrial membrane potential, increased reactive oxygen species, and promoted apoptosis. Inclusion formation triggered a collapsed mitochondrial potential, cellular quiescence, and deactivated apoptosis. We propose a revised model where sequestration of soluble Httex1 inclusions can remove the trigger for apoptosis but also co-aggregate other proteins, which curtails cellular metabolism and leads to a slow death by necrosis.
[Mh] Termos MeSH primário: Amiloide/metabolismo
Apoptose
Proteína Huntingtina/genética
[Mh] Termos MeSH secundário: Éxons
Células HEK293
Células HeLa
Seres Humanos
Proteína Huntingtina/metabolismo
Corpos de Inclusão/metabolismo
Potencial da Membrana Mitocondrial
Mutação
Espécies Reativas de Oxigênio/metabolismo
Ribonucleoproteínas/genética
Ribonucleoproteínas/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Amyloid); 0 (HTT protein, human); 0 (Huntingtin Protein); 0 (Reactive Oxygen Species); 0 (Ribonucleoproteins)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180213
[Lr] Data última revisão:
180213
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170504
[St] Status:MEDLINE


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[PMID]:28930532
[Au] Autor:Ahmad Rather M; Justin Thenmozhi A; Manivasagam T; Dhivya Bharathi M; Essa MM; Guillemin GJ
[Ad] Endereço:Department of Biochemistry and Biotechnology, Annamalai University, Annamalainagar, Tamil Nadu 608002, India.
[Ti] Título:Neuroprotective role of Asiatic acid in aluminium chloride induced rat model of Alzheimer's disease.
[So] Source:Front Biosci (Schol Ed);10:262-275, 2018 01 01.
[Is] ISSN:1945-0524
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Alzheimer's disease (AD) is the most common form of dementia, characterized by memory loss, cognitive impairment and personality disorders accompanied by diffuse structural abnormalities in the brain of elderly people. The current investigation explored the neuroprotective potential of asiatic acid (AA), a natural triterpene of on aluminium chloride (AlCl ) induced rat model of AD. Oral administration of AlCl (100 mg/kg b.w.) for 42 days significantly elevated the levels of Al, activity of acetyl cholinesterase and expressions of amyloid precursor protein, amyloid beta , beta and gamma secretases, glial fibrillary acidic protein, ionized calcium binding adaptor molecule 1, interleukins -1ß, 6, 4, 2, tumor necrosis factor alpha, inducible nitric oxide synthase, nuclear factor- k beta and cyclooxygenase-2 in the hippocampus and cortex  compared to the control group. Our observations suggested that AA treatment mitigated AlCl induced AD associated pathologies, which might be due to its multiple pharmacological actions. Further studies are necessary in order to explore the link between AlCl -mediated oxidative stress and associated apoptosis to establish its neuroprotective role in AD.
[Mh] Termos MeSH primário: Doença de Alzheimer/tratamento farmacológico
Fármacos Neuroprotetores/farmacologia
Triterpenos Pentacíclicos/farmacologia
[Mh] Termos MeSH secundário: Compostos de Alumínio
Doença de Alzheimer/induzido quimicamente
Doença de Alzheimer/metabolismo
Doença de Alzheimer/patologia
Amiloide/metabolismo
Secretases da Proteína Precursora do Amiloide/metabolismo
Peptídeos beta-Amiloides/metabolismo
Precursor de Proteína beta-Amiloide/metabolismo
Animais
Apoptose/efeitos dos fármacos
Cloretos
Modelos Animais de Doenças
Masculino
Estresse Oxidativo/efeitos dos fármacos
Distribuição Aleatória
Ratos
Ratos Wistar
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Aluminum Compounds); 0 (Amyloid); 0 (Amyloid beta-Peptides); 0 (Amyloid beta-Protein Precursor); 0 (Chlorides); 0 (Neuroprotective Agents); 0 (Pentacyclic Triterpenes); 3CYT62D3GA (aluminum chloride); 9PA5A687X5 (asiatic acid); EC 3.4.- (Amyloid Precursor Protein Secretases)
[Em] Mês de entrada:1712
[Cu] Atualização por classe:180213
[Lr] Data última revisão:
180213
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170921
[St] Status:MEDLINE


  9 / 13131 MEDLINE  
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[PMID]:28461187
[Au] Autor:Garg DK; Kundu B
[Ad] Endereço:Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
[Ti] Título:Hyperthermophilic l-asparaginase bypasses monomeric intermediates during folding to retain cooperativity and avoid amyloid assembly.
[So] Source:Arch Biochem Biophys;622:36-46, 2017 05 15.
[Is] ISSN:1096-0384
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:In obligate dimeric proteins of hyperthermophilic origin the question whether the native dimer is obtained by association of folded monomers or through concomitant folding and assembly of subunits has intrigued researchers. To find an answer we studied the folding of a dimeric enzyme l-asparaginase from Pyrococcus furiosus (PfA) for which we reported earlier that it unfolds cooperatively without populating folded monomeric intermediates. However, in the present study we report the finding of a folded monomeric intermediate of PfA under acidic condition. This monomer, although inactive, displayed secondary and tertiary structural features identical to the native protein and re-assembled to active dimeric form upon reversal of pH. The monomer is conformationally flexible and thermodynamically and kinetically less stable than the native dimer. Interestingly, when incubated at 60 °C the folded monomer, with exposed ANS-binding hydrophobic surfaces, spontaneously converted to amyloid fibrils. On the basis of our data we propose that PfA directly assembles into a multimeric form perhaps as an evolutionary adaptation to avoid accumulation of aggregation prone monomeric intermediates.
[Mh] Termos MeSH primário: Amiloide/metabolismo
Asparaginase/metabolismo
Dobramento de Proteína
Pyrococcus furiosus/enzimologia
[Mh] Termos MeSH secundário: Amiloide/química
Asparaginase/química
Estabilidade Enzimática
Cinética
Modelos Moleculares
Multimerização Proteica
Pyrococcus furiosus/química
Pyrococcus furiosus/metabolismo
Termodinâmica
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Amyloid); EC 3.5.1.1 (Asparaginase)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:180209
[Lr] Data última revisão:
180209
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


  10 / 13131 MEDLINE  
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[PMID]:29267402
[Au] Autor:Friedland RP; Chapman MR
[Ad] Endereço:Department of Neurology, University of Louisville, Louisville, Kentucky, United States of America.
[Ti] Título:The role of microbial amyloid in neurodegeneration.
[So] Source:PLoS Pathog;13(12):e1006654, 2017 12.
[Is] ISSN:1553-7374
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:It has become apparent that the intestinal microbiota orchestrates important aspects of our metabolism, immunity, and development. Recent work has demonstrated that the microbiota also influences brain function in healthy and diseased individuals. Of great interest are reports that intestinal bacteria play a role in the pathogenic cascade of both Parkinson and Alzheimer diseases. These neurodegenerative disorders both involve misfolding of endogenous proteins that spreads from one region of the body to another in a manner analogous to prions. The mechanisms of how the microbiota influences or is correlated with disease require elaboration. Microbial proteins or metabolites may influence neurodegeneration through the promotion of amyloid formation by human proteins or by enhancing inflammatory responses to endogenous neuronal amyloids. We review the current knowledge concerning bacterial amyloids and their potential to influence cerebral amyloid aggregation and neuroinflammation. We propose the term "mapranosis" to describe the process of microbiota-associated proteopathy and neuroinflammation. The study of amyloid proteins made by the microbiota and their influence on health and disease is in its infancy. This is a promising area for therapeutic intervention because there are many ways to alter our microbial partners and their products, including amyloid proteins.
[Mh] Termos MeSH primário: Amiloide/metabolismo
Proteínas de Bactérias/metabolismo
Microbioma Gastrointestinal/fisiologia
Doenças Neurodegenerativas/metabolismo
[Mh] Termos MeSH secundário: Animais
Encéfalo/patologia
Seres Humanos
Inflamação/etiologia
Inflamação/metabolismo
Inflamação/patologia
Doenças Neurodegenerativas/etiologia
Doenças Neurodegenerativas/patologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; REVIEW
[Nm] Nome de substância:
0 (Amyloid); 0 (Bacterial Proteins)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180202
[Lr] Data última revisão:
180202
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171222
[St] Status:MEDLINE
[do] DOI:10.1371/journal.ppat.1006654



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